Modern computers employ various forms of storage systems for storing programs and data. For example, various forms of disc drive systems have been designed to operate under the control of a computer to record information and/or retrieve recorded information on one or more recording discs. Such disc drives include hard disc drives which employ recording discs that have magnetizable (hard) recording material, optical disc drives which employ recording discs that have optically readable recording material, magneto-optical (MO) disc drives which employ recording discs that have optically readable magnetizable recording material, or the like.
Conventional disc drive systems typically include one or more recording discs supported for relatively high speed rotation on a rotary spindle. For example, FIG. 1 shows a side view of portions of a conventional disc drive system, including a conventional data storage or recording disc 200 supported on a spindle 210. A disc drive motor (not shown) is operatively coupled to the spindle 210 for rotation of the spindle and the disc supported thereon. A recording and/or reading head 220 is supported by suitable head support structure (not shown) adjacent the recording surface of the disc. To simplify the disclosure, FIG. 1 is shown with a single recording disc 200 having a single recording surface and a single head 220. However, other conventional disc drive systems employ multiple discs, double-sided discs (discs with recording surfaces on both surfaces) and multiple heads.
As shown in FIG. 1, the disc 200 has a central hub opening through which the spindle 210 extends. The disc 200 and spindle 210 are shown in a top view in FIG. 2. The spindle 210 extends through a central opening, which defines an inside diameter, of the disc. The disc is secured at its inner diameter (ID), in a fixed relation with the spindle 210, and is supported such that the outer diameter (OD) portion of the disc is free from contact with other components. In this regard, the disc is clamped at its ID to the spindle 210 and is free at its OD. When the spindle 210 is rotatably driven, the disc 200 is caused to rotate with the spindle 210. A top (not shown) which provides a protective cover for the disc is attached through the top of the spindle 210 and provides support for the spindle 210.
Typically, multiple open-center discs and spacer rings are alternately stacked on a spindle motor hub. The hub, defining the core of the stack, is cylindrical in shape and serves to align the discs and spacer rings around a common axis. The discs are secured to the hub by an annular clamp that fits over the hub. Collectively the discs, spacer rings and spindle motor hub define a disc pack assembly.
The surfaces of the stacked discs are accessed by the read/write heads which are mounted on a complementary stack of actuator arms which form a part of an actuator assembly. Generally, the actuator assembly has an actuator body that pivots about a pivot mechanism disposed in a medial portion thereof. A motor selectively positions a proximal end of the actuator body. This positioning of the proximal end in cooperation with the pivot mechanism causes a distal end of the actuator body, which supports the read/write heads, to move radially across the recording surfaces of the discs, such that the head may be selectively positioned adjacent any recording location on the recording surface as the disc is rotated.
In operation, the head 220 is moved in the radial direction to align or register with a desired track location on the recording surface of the disc. Once aligned or registered with the desired track location, the head 220 is operated to read or write information onto the recording surface at the desired track location. It is important to properly register the head 220 with the track location to effect accurate reading or writing operations on the registered track.
To assure that proper registration of the disc for reading and writing purposes can be achieved, the discs must not dislodge and move in the axial direction or the horizontal plane once they are positioned in the disc stack. Thus, the discs must be protected from nonoperational shock. Typically, the disc stack is susceptible to axial disc movement during handling, shipping and installation. In addition to nonoperational shock, the discs must be prohibited from axial movement during spinning as this could damage the head or cause it to misalign with the track it is currently reading.
Current systems use a clamp ring to secure the discs in place on the hub. The clamp ring is placed over the hub at the top of the disc stack. Various prior art systems have employed hub and clamp ring configurations such as that shown in the exploded view of FIG. 1, wherein a clamp ring is clamped onto a cylindrical hub by thermal contraction. However, in current systems, the clamp rings in such prior configurations have exhibited a tendency to slip off of the hub in high shock, thereby increasing the likelihood that the discs will move out of alignment on the hub. As such, a need in the industry exists for a cost effective system, apparatus and process that will increase disc protection from nonoperational shocks and movement.